The present invention relates to dispensing containers, and more particularly with respect to the illustrated embodiment relates to dispensers for the self-application of eye-drop medications.
Semi-viscus eye-drop medications for sustained release have been packaged in dispensers for self-application of the medication in the form of prefilled dispensers as described, for example, in U.S. Pat. No. 5,040,706. Such dispensers include an integral nozzle tip and a flexible plastic body of low density which can be manually squeezed to express drops from the nozzle particularly into the ocular cul-de-sac. However, the described integral container-dispensers have required prefilling with medication under sterile conditions since the flexible plastic dispensers cannot withstand autoclaving. Such dispensers also have a shelf life governed by the porosity of the thin, flexible, low density polyethylene or polypropylene from which the containers are molded which is subject to water vapor transmission loss. Furthermore, these dispensers employ a break-off cap structure resulting in a residual burr on the nozzle which interferes with proper size and direction of a dispensed drop into the eye, and the burr can also be hazardous when inadvertently contacted with the eye. Additionally, these dispensers are very difficult to mold since the integral, angled nozzle on the unitarily molded dispenser body requires both an internal core and a retractable core pin which must be perfectly aligned and mated in order to provide a continuous flow conduit and discharge port. These dual cores present problems in mating, breaking, and increased molding cycle time.
Another eye drop dispenser package is described in U.S. Pat. No. 4,871,091, in which the package walls are peeled to form a spout opening. The peeling of the walls creates potential for a torn edge at the spout discharge forming an eye hazard in dispensing the eye drops and no control over drop size and direction. These and other disadvantages are eliminated by the dispensers constructed according to the present invention.
While the present invention was developed and is disclosed herein in conjunction with a dispenser for eye medication, it is not intended that the invention be limited to this specific use. It is envisioned that there may be other uses for the dispenser where simple or limited dose applications are desired.